Question

How many numbers of 4 digit can be formed with figures 1, 2, 3, 4, 5,6, 7 such that each digit s taken only once, and the numbers always begin with 3?
O 180
O 210
O 100
O 120​

Answer 1

Answer:

The first digit must be selected from 1, 2, 3, 4. So there are four choices there. The other three digits can each be one of the seven. Thus there are 4*7*7*7= 1372 numbers.